SIfilliter_滤波器设计_pupili1m_MTI_

clear all; close all; clc; %constants c = 3E8; %(m/s) speed of light % [filename, pathname, filterindex] = uigetfile( { '*.wav','echo file(*.wav)'}, 'Pick a file'); % %read the raw data .wave file here % datafile=[pathname,filename]; % % if filterindex==0 % return % end % [Y,FS,NBITS] = wavread(datafile); load shiwai100mat;% 读取数据文件 %radar parameters Tp =454/441*(20E-3)/2; %(s) pulse time--- N = Tp*FS; %# of samples per pulse fstart = 2260E6; %(Hz) LFM start frequency for example fstop = 2590E6; %(Hz) LFM stop frequency for example %fstart = 2402E6; %(Hz) LFM start frequency for ISM band %fstop = 2495E6; %(Hz) LFM stop frequency for ISM band BW = fstop-fstart; %(Hz) transmti bandwidth BW=150e6; f = linspace(fstart, fstop, N/2); %instantaneous transmit frequency zpad = 8*N/2; %range resolution rr = c/(2*BW); max_range = rr*N/2; deltf=FS/zpad; Kr=BW/Tp*2; deltR=deltf*c*2/Kr; max_range=deltR*zpad; %the input appears to be inverted %check to see if triggering works % plot(trig,'.b'); % hold on;si % plot(start2,'.r'); % hold off; % grid on; %subtract the average ave = mean(sif,1); for ii = 1:size(sif,1); sif(ii,:) = sif(ii,:)-ave ; end figure(1); imagesc(linspace(0,max_range,zpad),time,sif); thresh=-40; title('未经过杂波抑制时域图') weight=(hanning(N)).'; sif=sif.*(repmat(weight,size(sif,1),1)); %RTI plot figure(2); v = (fft(sif,zpad,2)); v=20*log10(abs(v)); S = v(:,1:size(v,2)/2); m = max(max(v)); imagesc(linspace(0,max_range,zpad),time,S-m,[thresh, 0]); colorbar; ylabel('时间 (s)'); xlabel('距离 (m)'); title('未经杂波抑制处理频域图'); %% 二次相消器时域（加反馈） %-----------------递归二次相消杂波抑制（时域）-------------------% [b,a]=size(sif); K3=0.6; %要满足K1^2<4*K2 K4=8*(K3^2)/4; S_4=zeros(b-2,a); S_4(1,:) = sif(3,:)+2*sif(2,:)+sif(1,:); % s(t)-2*s(t-T)+s(t-2*T) S_4(2,:) = sif(4,:)+2*sif(3,:)+sif(2,:); for iiii=3:b S_4(iiii,:) = sif(iiii,:)+2*sif(iiii-1,:)+sif(iiii-2,:)+K3*S_4(iiii-1,:)-K4*S_4(iiii-2,:); end FFT_S_4=fft(S_4,zpad,2); v=20*log10(abs(FFT_S_4)); S = v(:,1:size(v,2)/2); m = max(max(v)); figure(3); imagesc(linspace(0,max_range,zpad),time,S-m,[thresh, 0]); colorbar; ylabel('时间 (s)'); xlabel('距离 (m)'); title('递归二次相消杂波抑制（时域）'); % %-----------------递归二次相消杂波抑制（时域）-------------------%